Plug-in systems with a plurality of contact chambers often require that the contacts contained therein to be of a small overall size because the diameters of lines to be connected are often barely smaller than the spacing of the individual contact chambers. In particular, when crimp contacts are used, problems of space may occur specifically in the region of the insulating crimp. When loading a plug housing, it is also important that the contacts can be introduced into the contact chambers with little force, without the contacts being bent in the process, because deformation causes additional problems with respect to space. This problem has previously been solved by limiting the admissible wire sizes for round or B-shaped insulating crimps.